Tonal Shift
by Logar3
Summary: All for One and All Might are fighting at Kamino when an adorable little powerhouse interrupts them.


His colleagues were down.

All around him laid his fellow Pro-Heroes, who had fallen victim to All for One's various traps and had their Quirks taken.

Ragdoll, Mt Lady, Endeavour, Gran Torino, Edgeshot, Miruko, Mrs. Joke, Fat Gum and many more lay unconscious around the Symbol of Peace.

**WOOSH**

The air held in the floating man's palm exploded outwards, clearing the large area. All Might flinched as he saw his friend's unconscious bodies slam against the edges of the field. It was night time, and the world was changing.

"How does it feel All Might? To see your colleagues like this? To know that right after I kill you, your successor, Itsuka Kendo, is next?!"

All Might, nearly broken, stood in front of All for One with his Quirk only activated in his right fist. He grimaced as he shifted his weight onto his back foot, prepared to take another blast from the two-century-old villain in front of him.

"That's where you're wrong, All for One! I will not be dying here today! The Symbol of Peace will not be brought down by your villainy!"

"Ah, but you see All Might, I've been going easy in this fight! The air blasts from before were just to wear you down, to show the world your true form! Now, I'll punch you with the ultimate combination of Quirks I have in me at this time!"

All for One's body grew to an enormous size, courtesy of Gigantification. The flames that spread from the bottom of All for One's mask showed the activation of Hellflame. "It's a shame that I couldn't get a hold of your colleague, Eraserhead, it would have made killing you so much easier!"

All Might's face paled as All for One's right arm grew grotesque, covered in metal spikes and lumps of flesh. He took a deep breath as the titan his foe had become took a step forward, throwing his fist down.

And then, everything stopped. Neither of the men could move a muscle and both of their Quirks flared down.

All for One made a very uncharacteristic noise of panic and All Might's eyes widened as they saw a wisp of green vanishing from the scene, and a small boy licking his fingers.

* * *

_**Five minutes earlier**_

"Mum, Kuro! Look at the new Quirk dad gave me!"

Izuku jumped up into the air with a gust of wind from his feet, before spinning and shooting another gust at the roof, changing his trajectory and landing on the dining table.

Inko smiled at the boy, willingly repressing her knowledge of where that Quirk had come from. She knew what her husband did, but couldn't find it within herself to stop loving the man.

"That's very impressive, Izu! And look how good you are with it already! You move like a pro!" She gave praise to her son, her baby boy, only eleven years old, even when he was born with his father's Quirk.

It was a mutation, he was able to take Quirks from a range of about 3 metres currently, but Izuku got the benefit of taking the knowledge of how to use the Quirk from the person as well.

"_Mum!_" Izuku whined. "You know that's just my Quirk working! It's the fact that I have **Jet** at all that's so cool!" He looked over at Kurogiri. "How cool is this Quirk?!"

Kurogiri hummed, nodding his head. "It's very cool, Master Izuku. Your father is a very generous man to have given you such a quality Quirk."

Of course, Kurogiri had been the primary way that All for One had gotten his hands on **Jet**, warping the old man while he was sleeping into a small box, allowing for All for One to have access to the man's Quirk without him flying away at Mach 2.

The TV behind them changed to a birds-eye view of Kamino ward, and Izuku could see All Might on the screen. "OOO! Mum! All Might's fighting someone! **Identify!**"

'**Identify'** was a Quirk that his dad had given him that could tell him the name and Quirk of anyone he used it on. So imagine little Izuku's surprise when the Quirk was telling him that the man All Might was fighting was none other than Hisashi Midoriya.

"DAD!?"

Kurogiri froze, realising how bad it was that Izuku had seen this. "Master Izuku wai-" He was cut off as he felt the mist around his body dissipate and flow towards Izuku, whose hair turned into light green mist.

A green portal appeared in front of the boy, and he jumped through.

* * *

"**Papa!** What do you think you're doing! How could you be hurting All Might! You said you would stay away from him! You promised me!"

All Might couldn't believe what he was hearing. One second, he thought he was about to die, then the next, both he and All for One, the strongest foe he had ever fought, seized up as soon as this boy appeared.

'_Papa… Is this boy All for One's son!?'_ All Might struggled as hard as he could, but none of his muscles would budge. "Young Man! What are you doing here? And how have you immobilised us!?"

The boy pouted at All for One, sending All Might reeling again, before turning to him. "Sorry Mmister All Might, but I used a Quirk called **Bloodcurdle** to stop you both! You're both bleeding all over the place so it was fairly easy."

All Might recognised that Quirk. It was the Hero killer Stain's Quirk. Did this boy have **All for One** as well?!

"Young man, we are going to have a very serious discussion about this when we get home, you hear me! Let me go this instant!" All for One yelled at the small child.

But the boy didn't cower like All Might had seen so many others cower before the villain. "NO! You promised me you would stop doing your bad guy stuff, and you broke that promise! And you took a bunch of heroes' Quirks as well!"

He waved his hands, a soft green light emanating from them, and a few green lines spread from All for One to the boy, who went through rapid changes as he took the Quirks from his dad. Then, while the two powerhouses were still down, he walked around and gave all of the Quirks back to their rightful owners.

He could feel **Bloodcurdle's **effects about to end for All Might, and his dad only had about a minute and a half left, so he walked over to the prone fighters.

"Papa, we're going home, and you're stopping being a bad guy, okay? And Mister All Might, I'm really sorry about my dad doing all of this, but I know Mum is going to chew him out for it!"

Izuku created a portal underneath All for One, sending the man directly back to the couch, where he knew his Mum would be waiting. All Might watched this with wide eyes when suddenly, he could move.

He stood up quickly and walked over to the boy. "Young Man, you must bring your father back here. He needs to be punished for what he has done."

The boy looked up at All Might, at one of his two idols, the other being his Dad, and shook his head, giving the man his best puppy dog eyes. "Can't you just let us go, Mr All Might? Mum is going to make him stop, and I gave all the Quirks back!"

All Might shook his head grabbing the boy by the shoulder. "I'm sorry, young man, but I can't do that. But I do have a question for you." The boy nodded. "Why did you give them all their Quirks back? Surely you wanted to keep some for yourself?"

All Might was expecting a few different responses to that, but he wasn't expecting the boy to shake his head. "No, I only take Quirks from bad people who use them to hurt others! And besides, isn't giving them back what a hero would do?"

All Might's eyes widened at the statement. The son of All for One, arguably the most powerful supervillain in the world, wanted to be a hero? While his mind was screaming at him, his heart told him what to say.

"Of course it is, Young Man! And if you want to be a hero, I'm sure you'll be a great one!" All Might patted the boy on the back. "But I have to let you know that your father is still a wanted criminal. He will be caught eventually."

Izuku shook his head. "Mum's gonna make him stop bad guy stuff, not running away. And with the number of Quirks that Dad has, I doubt you'll find him anytime soon."

A portal appeared behind Izuku as he handed something to the stunned Hero, before turning away. "See you when I'm a hero, Mister All Might, sir!"

All Might was too shocked to stop him.

* * *

The news was going ape-shit.

The biggest fight of the year, All Might VS an unknown villain that could go toe-to-toe with him, and then the villain's son appears, talks down the two fighters, sends the villain away, and escapes from All Might?!

The story of the century.

Every news outlet was covering it, the story of the young cryptid. According to all the databases, no Quirk like the portal Quirk he showed off existed! This fact sent the media into even more of a fit.

All Might was sitting in Nezu's office, staring blankly at the mouse-bear-dog thing as he drank some tea. Right before he left, the boy had handed All Might a small purple capsule, as well as a note.

The note read as follows;

* * *

'_Mr All Might sir!_

_I know you have no reason to trust me, as my dad is a really bad bad guy, and you are the best good guy, but I would like to offer you this._

_The green thingy (a catsule or something?) is from one of the Quirks that dad gave me, called __**Senzu Creation**__. It takes a lot out of me to create one, meaning that I will probably be asleep while you read this, probably for the next few days._

_I think it might be able to heal you! Dad says he hurt you a while ago, and again, I'm really sorry about him. But the Senzu should be able to heal your injuries over the course of a week, and get you back to being the awesome hero you can be again!_

_Good Luck, and Best Wishes_

_**I.M**__, your biggest fan!_

* * *

Nezu had just read the note and was considering its offer.

His Quirk-powered thoughts were going a mile a minute, going over every possible scenario, before eventually coming to a conclusion.

"Well, All Might, I say you give it a try!" The man in question did a spit-take, losing half of the tea he had been drinking.

"Nezu! Are you sure about this?! What if it's a trap set by All for One?!" Nezu just shrugged at this, as if the answer was obvious.

"Well it wouldn't really matter now, would it? From what you told me, you can only be in your hero for about 20 minutes a day, and the world has already seen your weakened body! And by the looks and sounds of it, this son of his seems to want to be a genuine hero. I doubt he would poison you and ruin his chances of that."

All Might gulped but nodded. If anything, he trusted Nezu's analytical skills and decision-making ability. "Alright sir, I'll do it. And either way, it says it will work over a week, right? If it is poisoned, we have a week to whip up an antidote!"

Nezu clapped, smiling. "Exactly! So, have at it!"

All Might gulped, before placing the Senzu capsule in his mouth and washing it down with his tea. After a few minutes, he could feel an odd feeling in his chest.

And after a week, the world had its Symbol of Peace back, and All Might couldn't be more grateful to the strange boy that stopped the fight.

* * *

"_**I AM HERE, COMING THROUGH THE DOOR LIKE A NORMAL PERSON!"**_

It had been a few years since he had eaten the Senzu capsule, and he hadn't felt this good since his prime. He stepped into the classroom to see Aizawa asleep in the corner of the room, and the crowd of rowdy 15-year-olds quieting down in awe of him.

All except one. One boy in the front row gave him a smile, staring him right in the eyes. Eyes All Might recognised.

"Long time no see, All Might, told you I'd see you when I was a hero!"


End file.
